An optical fiber is a glass or plastic fiber designed to guide light down its length by total internal reflection. Although fibers can be made out of transparent plastic or glass, most often, fibers used in long-distance telecommunications applications are glass, due to a lower optical attenuation. Both multi-mode and single-mode fibers are used in communications, with multi-mode fiber used mostly for short distances and single-mode fiber used for longer distance links. Oftentimes, these fibers are used in communication which permits digital data transmission over longer distances and at higher data rates than electronic communication.
In communication service provider applications, optical fibers are bundled as cables. Because light propagates through the fiber with little attenuation compared to electrical cables, use of fiber optic cables is especially advantageous for long-distance communications. By using optical fiber cables, long distances can be spanned with few repeaters. Additionally, the per-channel light signals propagating in the fiber can be modulated at substantially higher rates than conventional coaxial cables.
Today, optical fibers are becoming more and more common as a medium for networking and telecommunications. For example, television and Internet service providers are using fiber optics to deliver their services to customers in homes, multi-residence buildings and office buildings. Unfortunately, many of these structures are older which makes installation sometimes cumbersome and costly as, many times, optical cables must be fed through a structure's existing plumbing, electrical and heating ducts.